Why Does My Dog Vomit Blood?

By Josie F. Turner, Journalist specialized in Animal Welfare. Updated: September 2, 2018
Why Does My Dog Vomit Blood?

See files for Dogs

If your dog secretes blood from any passage, there should always be concern and generally requires medical attention. If your dog vomits blood, then your reaction will likely be even more visceral. It is a worrying sight, so the first thing we need to find out by way of explanation is from where is the blood coming. We will also need to know if it is fresh blood or old blood which has been partially digested. As for the cause, there are many possibilities.

This is why AnimalWised answers the question why is my dog vomiting blood? by looking at the common possible causes. We only do so in the proviso that this is not a replacement for taking your dog to the vet for a thorough diagnosis.

You may also be interested in: Why Does my Dog Vomit Bile?

Dog vomiting blood

Before we explain the possible reasons your dog may be vomiting blood, we should know that this blood may have various origins. If the blood you see is indeed part of vomit, then it could be coming anywhere from the mouth to the stomach. However, the first thing we should do is check their oral cavity (the mouth) to see if there are any wounds or lesions which may explain the bleeding. Sometimes a wound on the gums or tongue can be created by a piece of shattered bone or stick. This bleeding may have mixed with vomit to give the impression it is coming from somewhere inside their body.

Even though it is in the mouth, bleeding from this area can be abundant. Although, in general, it will be less of a serious issue than internal bleeding, it can still be problematic. If we examine their mouth and there is an anomaly such as a lump, a broken tooth or a foreign body, we should contact a veterinarian.

The vomiting of blood which originates in the digestive system is known as hematemesis. The bleeding may also come from the respiratory system. The blood can appear fresh, usually in streaks or clots. If the blood has started to be digested, it will be darker in color. Additionally, a dog may vomit blood with foam, mucus or excess liquid.

Sometimes a dog will vomit blood, but also have some appear in its stool. These stools, known as melena, will be of a very dark color thanks to containing digested blood. Finally, we must see if a one-off episode of acute vomiting occurs or if we observe vomiting over several days. You need to consider this data as well as looking at other symptoms such as pain, diahrrea or weakness. This will prove useful when bringing your pet to the vet.

Why Does My Dog Vomit Blood? - Dog vomiting blood

Inflammatory diseases of the digestive system

If your dog has inflammation of the bowel or any other part of the digestive system then it is common to see blood in the vomit or stool as a symptom. However, this doesn't happen 100% of the time. If we see the dog vomiting blood, they often will not want to either or drink. We must seek veterinary advice as whenever there is bleeding there are conditions favorable to developing an infection.

Additionally, losing fluid without being able to replenish them means dehydration is a great risk. In turn, this aggravates the general clinical picture. The causes of inflammation may be various, but a particularly serious one is parvovirus with acute infectious enteritis. This particularly affects puppies and has a high mortality rate. Being a virus, there is no better treatment that prevention. This is done by vaccinating puppies from the ages of 6 to 8 weeks.

Presence of foreign bodies

It is relatively common for dogs to ingest all sorts of objects, especially when they are puppies or have a voracious appetite. These objects can be stones, sticks, bones, toys, hooks, ropes, etc. Some contain sharp edges and therefor can cause considerable damage to the digestive system when swallowed. This can even include perforation of internal organs.

If we suspect the ingestion of a foreign body as the cause of blood in our dog's vomit, we should go to the veterinarian immediately. By carrying out and x-ray it is sometimes possible to distinguish the swallowed object and its location. Other times, it is necessary to carry out an endoscopy with which the foreign body can sometimes be extracted. If this is not possible, the treatment will be abdominal surgery. To avoid these situations prevention is essential. This can be down by not leaving choking hazards around the house and only offering safe toys and not those made of dangerous materials.

Why Does My Dog Vomit Blood? - Presence of foreign bodies


Whether accidental or intentional, poisoning can also explain why our dog vomits blood. Some substances, such as rodenticides, act as antocoagulants and cause spontaneous hemorrhages. In addition to vomiting, symptoms may include nosebleeds and/or rectal bleeding. Immediate veterinary attention is required and the progress will depend on the substance ingested and its quantity in relation to the weight of the animal. If we know what poisonous substance the dog has ingested, we must tell the vet.

To prevent accidental poisoning, we need to ensure our pet lives in a safe environment, prohibiting access to toxic products such as household cleaners or caustic solutions. When you take them for walks or if they have access to the outside, we must also make precautions. This is because there may be garbage, hazardous discarded material or even plants which contain substances poisonous to dogs. Always keep an eye on them and ensure you stop them from eating anything if you are unsure what it is. Rapid intervention may be the key to avoiding poison risks. If poisoning occurs, it is usually treated with vitamin K and blood transfusions may possibly be required.

Renal insufficiency

Sometimes the cause of vomiting blood in a dog is due to an underlying systemic disease such as kidney failure. In this case, the reason the dog vomits blood is as a consequence of the kidneys being unable to eliminate waste products properly. The accumulation of toxins in these waste products is what causes the symptoms.

Although the kidneys are essentially failing, they are able to compensate for a long time. When we finally register the disease, they are often already compromised. This insufficiency can occur in an acute or chronic way. In addition to vomiting blood from gastrointestinal bleeding, we can see that our dog drinks and urinates more, seems apathetic, is thinner, has drier hair and has a breath which smells of ammonia. Sometimes mouth ulcers and diahrrea are also present.

We can confirm the problem through a blood and urine test. The prognosis will depend on the development of the disease. In chronic cases, treatment usually consists of a specific diet for dogs with renal failure as well as medication. Acute renal failure requires intensive veterinary care with fluid therapy and intravenous medication.

Why Does My Dog Vomit Blood? - Renal insufficiency

Gastric ulcers

An ulcer consists of lesions in the mucosa of the digestive system. They can be superficial or deep and present themselves in various sizes. They may also be the explanation as to why your dog is vomiting blood. Among the causes of ulcers is the use of anti-inflammatory drugs (NSAIDs). Ulcers cause vomiting, but may also be accompanied by anemia and weight loss.

Digested, fresh or clotted blood may be present in these vomits. It is a serious situation since considerable hemorrhage can occur quickly, causing the dog to go into shock. Stools may also appear blackish due to the presence of blood. In addition, the ulcer may end in perforation which can cause peritonitis. Veterinary attention is required and the prognosis is reserved until after examination.

Other causes of vomiting blood in dogs

As we said at the beginning, there are many potential causes of blood being present in a dog's vomit. In addition to the ones mentioned above, there are also potential causes found with:

  • Tumors (more frequent in older dogs)
  • Liver or pancreatic diseases
  • Injuries caused by accidents such as falls or collisions
  • Disorders of coagulation

For these causes or those mentioned above, the veterinarian will need to carry out a series of diagnostic tests. This includes examination and/or laboratory tests such as blood, urine and faeces tests, x-rays, ultrasounds, endoscopies or even exploratory laparotomy. Wherever there is bleeding, surgery may be the required option. This is because it can often be a serious condition which threatens the life of our dog. As we have already seen, both treatment and prognosis will depend on the origin of the blood in the vomit as well as the speed with which a diagnosis is sought.

Why Does My Dog Vomit Blood? - Other causes of vomiting blood in dogs

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Why Does My Dog Vomit Blood?, we recommend you visit our Other health problems category.

Write a comment

Add an image
Click to attach a photo related to your comment
What did you think of this article?
Why Does My Dog Vomit Blood?
1 of 5
Why Does My Dog Vomit Blood?

Back to top